The present invention relates to an anti-lock brake system of the type wherein the pressure applied to the wheel brakes can be decreased by discharge of the pressure fluid by way of a return line, and including a pump whose suction chamber communicates through a suction line with a reservoir.
A brake system of this type is known from German published patent application P 36 01 914. That known brake system provides for the return line to connect to the outlet valves, on the one hand, and to the reservoir, on the other hand. The total capacity of the pump is required in this event and great pump efficiency is of utmost importance. In particular in piston-type pumps with suction valves and pressure valves, the pump's suction efficiency at very low temperatures, that is high viscosity of the fluid, has been a problem.